Toner and developer, toner container, process cartridge, image forming apparatus, and image forming method using the same

Abstract

To provide a toner containing an ethyl acetate-soluble polyester component and an ethyl acetate-insoluble polyester component, wherein the toner is granulated in an aqueous medium, the ethyl acetate-insoluble polyester component is obtained by elongating and / or cross-linking a modified polyester resin during granulating and / or after granulating, the modified polyester resin is produced by condensation polymerization of an acid component and at least one type of diol compound selected from aliphatic diol and alicyclic diol in the presence of a catalyst, and the mass average molecular weight of the modified polyester resin is 10,000 to 100,000.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001] This is a continuation of Application No. PCT / JP 2006 / 309766, filed on May 10, 2006.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a toner for developing static charge images in electrophotography, electrostatic recording and electrostatic printing, and a developer, a toner container, a process cartridge, an image forming apparatus and an image forming method using the toner respectively. [0004] 2. Description of the Related Art [0005] The image forming method for electrophotography, electrostatic recording and electrostatic printing, etc. includes development step in which a toner contained in a developer is attached once to an image bearing member such as photoconductor on which a static charge image is formed, transferring step in which the toner is transferred from the photoconductor to a transfer medium such as transfer paper and fixing step in which the toner is fixed on the pap...

AI Technical Summary

Benefits of technology

[0033] It is an object of the present invention to provide a toner which has excellent low-temperature fixing property and capable of maintaining heat-resistant storage property and forming an image of high quality which exhibits appropriate developability for prolonged periods, and an image forming apparatus and an image forming method using the toner respectively.

[0067] The each toner of the above first, second, third and fourth embodiments are capable of pursuing excellent low-temperature fixing property and offset resistance simultaneously to form appropriate images of high resolution.

Problems solved by technology

This method is significantly effective in terms of preventing offset of the toner, however, since a feeding unit for offset preventing liquid is needed making the fixing apparatus more complicated, it is disadvantageous for energy conservation and moreover, separation between layers making up the fixing roller is induced by the oil application leading to facilitation of short life span of the fixing roller.

When such fixing apparatuses are used for prolonged periods, the toner accumulated on the fixing cleaning roller is melted by heat and causes inverted hot offset, a defect caused by the melted toner which is reversely transferred to the fixing rollers or pressure rollers.

However, decreasing the fixing temperature of the toner poses a problem of difficulty in securing fixing temperature regions (hot offset resistance) and maintaining heat-resistant storage property.

However, when molecular weight of the toner binder is reduced in the low molecular weight regions or fixing temperature of the toner is lowered by increasing the ratio of low molecular weight components, storage stability in high-temperature regions is degraded and fusion during running becomes notable and also, troubles such as deterioration of image quality due to the change in charged amount may likely to occur.

However, when the toner, which is produced by the above methods, is used with the decreased fixing roller temperature, fixing becomes insufficient and more improvement of low-temperature fixing property is required.

As one of the methods to fulfill the requirements, temperature-responsive property of the toner may be improved by decreasing the heat capacity of the fixing member such as heat rollers; however, it is not satisfactory.

Moreover, an attempt to add specific non-olefin crystalline polymers in binders for the purpose of improving low-temperature fixing property (JP-A No. 62-63940) and an attempt to employ crystalline polyesters (Japanese Patent (JP-B) No. 2931899) have been proposed, however, molecular structure and molecular weight of the polyester resins are not optimized in these proposals.

Furthermore, it is impossible to fulfill the specifications of the DSM program even if these known conventional arts are applied, and the establishment of low-temperature fixing technology which is more advanced than conventional technologies is needed.

Because of these issues, a toner having an excellent low-temperature property and high hot offset generation temperature have not yet been obtained by controlling heat properties of the resin itself.

It is possible to produce the toner which has excellent properties to some extent by pulverization; however, material selection is limited.

Because of this requirement, fusion mixed toner composition must be sufficiently brittle.

When the toner composition is actually pulverized to become particles, the mass average particle diameter of the toner must be reduced, for example, in order to obtain copied images with which particle diameter distribution of broader region is likely to be formed with appropriate resolution and tone, and there is a disadvantage of having extremely low toner yield because fine powder of 4 μm or less particle diameter and coarse powder of 15 μm or more particle diameter must be removed by classification.

Moreover, it is difficult to disperse colorants or charge controlling agents evenly in a thermoplastic resin in pulverization and uneven dispersion brings harmful effects on flowability, developing property, durability and image quality of the toner.

However, it is difficult to produce the toner by using polyester resins which are advantageous in low-temperature fixing properties in these manufacturing methods of the toner.

However, low-temperature fixing properties and toner productivity were not sufficient in any of these proposals.

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